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        Build Log GWS Cargotrans Quad "EC-130H Compass Call" Build Thread

#1 crxmanpat Feb 19, 2006 11:46 PM

GWS Cargotrans Quad "EC-130H Compass Call" Build Thread
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OK, so I finally started building the kit I picked up at the AZ Electric Fly 3 weeks ago. As I had stated on the other Cargotrans thread, my build will be a model of the plane I flew on when I was in the Air Force. This is the EC-130H "Compass Call" airborne jamming platform. The pic below is of tail number 1862, which is one of the few of these I have flown on.

After checking to make sure all the parts were in the kit, I began sanding off all the foam injection "dimples" and imperfections. I used 240 grit paper on a foam padded sanding block. I then cut out and hinged all the control surfaces. I will be applying the two-tone paint scheme prior to gluing all the parts together, and will touch up after final assembly and filling the cracks with spackling.

I have considered several of the modifications that have been presented in other build threads, and will most likely do the ones like stick motor mounts, relocate battery farther forward, engine wiring harness, etc. I have already removed the filler styro from the main gear wheel wells to keep the wheels from binding.

Since I will have so much extra stuff on the tail assembly, I will use carbon fiber pieces and low diameter fishing monofilament to help keep the weight down. Detailed pics will be provided during the rest of the build.

#2 CSI Feb 20, 2006 02:03 AM

This is an interesting build and I am glad someone else appreciates the Compass Call! I imagine stringing all those wires for the antenna clothesline in the back will be quite a chore. What are you going to use to make the trapeze out of? I'm not sure how important it is for adding weight to the back of the -130 model, I hope it isn't as severe a penalty as on the warbirds?! I look forward to seeing this model finished. I have a few pictures from my time there in the 41st, but unfortunately none are digital. I have been wanting to build a C-130 myself, but I have way too many other planes ahead of it. I can't decide whether to go EC or AC variant, maybe both (can't let my wife see this!)?
Good luck with the build.

#3 crxmanpat Feb 20, 2006 01:29 PM

Ken, thanks for the kind words. For the trapeze, I'm going to use as much carbon fiber as possible. My LHS sells CF in sticks too, not just rods, so that is what I will use. For the trapeze wiring, I'm thinking of using very small diameter (like 4lb test) fishing monofilament, then painting it. I will have to lay out a sketch diagram, cover with wax paper, then assemble the wiring. I've never tried CA'ing mono before, I hope it works. If all else fails, I may have to use thin wire.

Weight will definitely be a problem. I may have to stuff most of the electronics further forward than the plans call for. Hopefully the rigging won't add too much. I'm also debating on whether or not to add the wing tanks. The model looks good without them, but then it won't be a "scale" model. I'll fully assemble it first, see how much it weighs, and then decide if I can afford the added weight. I also want to find some 4-blade props, but I don't think they are available in this size. I think someone else had made some of his own, but I guess you don't notice it in flight.

When were you in the 41st? I was at DM from Oct '89 - Mar '90, then Sembach (43rd) from Mar '90 - Feb '91.

#4 crxmanpat Feb 26, 2006 08:37 PM

Progress Report
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I have made significant progress in this build. The next few posts will detail my build to this point. Note that I did not follow the instructions as laid out in the manual as I knew I would be tail heavy in the build. So in order to balance things out better, I would need to move the radio components around some. Namely, I would be mounting the rudder/elevator servos forward of the central bulkhead.

Step one was to sand out all of the mold marks. I also filled all indentations in the foam with lightweight spackling. Everything was sanded down to a smooth finish. I also cut and hinged all control surfaces in the initial steps.

As others have done, I removed the styrofoam from the aft section of the wheel well so that the rear tires wound not bind on landing.

#5 crxmanpat Feb 26, 2006 08:49 PM

Progress Part 2
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Next I started working on the wing. After joining the wing halves together and gluing in the carbon fiber support rod, I worked on assembling the motors. I opted for the stick mounts as described in another build thread, as I too did not want to rely on the extremely thin plastic cowlings for support. I used lightweight basswood for the motor mounts, and included a block in the rear to act as a motor stop.

Jeff Hunter (Jarhead) used some d-sub connectors from Radio Shack to connect all the wing wiring together, which I thought was an excellent idea, so I did the same thing. After getting all of the motors assembled and the wiring completed, I mounted the aileron servos and glued the motors to the wing. I used clear packing tape to cover the channels that contained the wiring.

#6 crxmanpat Feb 26, 2006 08:58 PM

Progress Part 3
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After completing the wing, I then moved on to the fuselage. I started by mounting the rudder and elevator servos forward of the central bulkhead. I then ran the pushrod tubing to the appropriate locations. This is the same as was done in the E-Zone review of this kit. This would help with my CG without having to add dead weight to the nose. I also expanded my battery tray to accept my 3S 1000mAh Lipo pack, but I left it tight enough so that it would not shift in flight. I made it so that the majority of the pack would also sit forward of the CG.

I then hooked up my Rx and ESC, turned on my radio, plugged in a battery and centered my servos. This was critical as once I closed the fuse, I would not be able to have access to my rudder/elevator servos unless I cut into the fuse. In the end, I may wind up creating an access hatch anyway, but only time will tell.

Satisfied with the servos, I glued in the assembled nose gear and joined the fuse halves together. I also mounted the tail surfaces and connected the pushrods.

#7 crxmanpat Feb 26, 2006 09:07 PM

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The last thing I have done was assembled the main landing gear, and then buttoned everything up to see how she looked. I tried to run up the motors with the props attached, but they will need to be CA'd on as the set screws do not work. Or, I may try to rig up a mounting system as described in another build thread.

Next step will be to assemble the trapeze and wire system, carve out the bubbles for the rear fuse section and the external wing fuel tanks, and paint. I only get about an hour or so each evening during the week to work on this, so it's been slow going. But now that the majority of the assembly is complete, I can concentrate on the finishing touches. Will update with more progress in a few days.


#8 Aerobatman Feb 26, 2006 10:47 PM

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Great job on your build. My 'Cargotrans' is now complete sans paint. I noticed you used the d-sub connector for the wing wiring harness to fuse connections. Great idea. I found that you can save about 6 grams of weight by removing the metal cage around the connector on both sides. I used my Dremel with a grinding stone to remove the crimps, then each half of metal peels off. Here's what my connection now looks like. It's also easier on the fingers without the sharp stamped metal edges. I'm waiting for some warm weather to get my airbrush out!

#9 crxmanpat Feb 26, 2006 11:04 PM

Awesome Aerobatman, thanks for the advice, I need all the weight savings I can find because of what I will be adding to the model. I will be sure to get my dremel out and remove those metal covers. I hope to be firing up my airbrush this week, looks like we'll be near 80* most of the week (boy I love living in the south!).


#10 CSI Feb 27, 2006 01:02 AM

I love your work, very nice. Your build really makes me want one of my own!
Have you thought about using the Spiderwire braided monofiliment for your wires? I have a spool of it that I have used for many projects and it is great, strong stuff. Much easier to work with than regular monofiliment, also a bit pricier too. Very easy to paint. I can't see how it would add much weight if you made the wing tanks out of a blocks of foam, and definitely adds to the realism.
I was in the 41st from 92-96, Commander was LTC Crystal. Chief pilot was Whittimore :eek: I went of to gunships at Hurlburt after that.
Good luck on the rest of the build, looks great.

#11 crxmanpat Feb 27, 2006 02:00 PM

Electronics setup

Thanks for the Spiderwire suggestion. I was thinking of that too (or Fireline), and yes I'm sure it's easier to work with. Heck, if I can find some in black, I won't need to paint at all! Cost is not a concern.

I've neglected to add the electronics specs for this, so here they are:

Stock brushed EDP50 motors
GWS ISC 480Li speed controller
4 E-flite S75 sub-micro servos
Hitec Electron 6 Rx

Power will be provided by a TP1320 2S lipo.


#12 Ericmf Feb 27, 2006 03:09 PM

nice work CRX. I've just completed my second C-130. it's a lot easier after you've made all the mistakes on the first one, and done a pile of repairs!!.

it's not clear where you're putting the battery. is it on the bottom? if so, I think you need some room for airflow. my 3 cell 1050's get a little hotter than I'd like, even in -10 C I flew in this morning. I have the servos in the normal location, and have an extra one in the middle to actuate the cargo door. as a result the CG would be too far back. so I cut a hole for the battery to sit in so that it sticks though the main firwall at the bottom. it's tight enough that it won't move, but I think it needs more air flow.

One other slight Mod I made, I bent slightly higher guage wire (2mm) for the landing gear. I just did the rear one, since it takes brunt of the landing force. I also have a aeronitical lighting system for night flights. total flighing wieght with battery is 540g

#13 crxmanpat Feb 27, 2006 04:08 PM


Originally Posted by Ericmf
it's not clear where you're putting the battery. is it on the bottom? if so, I think you need some room for airflow.

Yeah, the battery will go in the intended location. But as a result of my mod, about half of it will be sticking out into the empty space in the forward fuse. I didn't think about ventilation for it. I've gotten so used to flying in the cold that my batteries are never that warm after flights. But they are all well ventilated. I may have to devise some type of duct system for cooling.

I would love to do lights, but since I am already adding weight elsewhere, I will have to see what I am AUW before adding anything else. I would love to be able to turn on landing lights on approach! :cool:


#14 Aerobatman Feb 27, 2006 07:16 PM

I wedge my 1570 2s into a widened slot ahead of the stock battery tray. It fits nice and snug and doesn't need velcro to hold it in place. I left a 1/2" air gap on each side of the battery. There IS stock cooling air flow through the fuse. I found that there's a gap behind the nose wheel, this leads to battery compartment, up into the servo bay and out through an 'exhaust' hole under the stabilizer.

#15 Chazzman Feb 28, 2006 07:43 AM


I just ordered my Cargo trans

can you turn me on to the various threads out there so that i can read up before I start?

Also do you guys paint the plane before building? What kind of paint is suggested?

Any help will be appreciated?

Also any sugestions on where to buy the servos and such?

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